肿瘤来源的外泌体包裹 miR-34a 在体外条件下促进结直肠癌细胞的凋亡，并抑制其迁移和肿瘤进展。
Tumor-derived exosomes encapsulating miR-34a promote apoptosis and inhibit migration and tumor progression of colorectal cancer cells under in vitro condition.
机构信息
Department of Immunology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran.
Basic and Molecular Epidemiology of Gastrointestinal Disorders Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
出版信息
Daru. 2021 Dec;29(2):267-278. doi: 10.1007/s40199-021-00400-0. Epub 2021 Aug 17.
BACKGROUND
MicroRNA (miR)-34a, as a master tumor suppressor in colorectal cancer (CRC), could regulate multiple genes participating in tumor proliferation, invasion, immune evasion, and inflammation-induced progression. Exosomes, as novel nano-carriers, were found to be capable of shuttling crucial mediators to various cells. Since the conventional CRC therapeutics currently are a matter of debate, implication of microRNAs in malignancy remedies have been addressed illustrating promising outlooks.
OBJECTIVES
In this study, we aimed to investigate the delivery of miR-34a to CRC cell line CT-26 by encapsulating into tumor-derived exosomes (TEXs), in order to evaluate the anti-proliferative and progressive effects of the novel nano-carrier complex under in vitro condition.
METHODS
Exosomes were purified from the starved CT-26 cells and then enriched by miR-34a using the calcium chloride (Cacl) modified solution. Following the detection of miR-34a expression in the enriched TEXs, the viability of CT-26 cells treated by multiplicity concentrations of either TEXs or TEX-miR-34a was examined. Moreover, the apoptosis rate of the cells was evaluated, and the migration of CT-26 cells subjected to both TEX-miR-34a and TEX was also measured. Thereafter, the expressions of miR-34a target genes, as IL-6R, STAT3, PD-L1, and VEGF-A, which play roles in tumor progression, were determined in the treated CT-26 cells.
RESULTS
The viability of CT-26 cells was harnessed following the treatment with TEX-miR-34a and the apoptosis levels of the cells were also observed to be enhanced dose-dependently. TEX-miR-34a was able to diminish the migration rate of the TEX-miR-34a treated cells and the expressions of IL-6R, STAT3, PD-L1, and VEGF-A were significantly restricted. Moreover, TEXs alone increased the apoptosis rate of tumor cells and repressed the proliferation and migration of these cells which were boosted by enrichment of TEXs with miR-34a.
CONCLUSION
Exosomes isolated from the starved CT-26 cells were found to have a potential to deliver miR-34a into tumor cells properly with high functionality maintenance for miR-34a in case of regulating genes related to tumor progression and TEXs which showed no positive effect favoring cancer cells, presumably act as a favorable adjuvant in the CRC therapy.
背景
微小 RNA（miR）-34a 作为结直肠癌（CRC）中的主要肿瘤抑制因子，可调节参与肿瘤增殖、侵袭、免疫逃逸和炎症诱导进展的多种基因。外泌体作为新型纳米载体，被发现能够将关键介质转运到各种细胞中。由于目前传统的 CRC 治疗方法存在争议，因此已经研究了 microRNAs 在恶性肿瘤治疗中的作用，显示出了有前景的展望。
目的
在这项研究中，我们旨在通过将 miR-34a 包裹到肿瘤衍生的外泌体（TEXs）中来向 CRC 细胞系 CT-26 中递送 miR-34a，以便在体外条件下评估新型纳米载体复合物的抗增殖和进展作用。
方法
从饥饿的 CT-26 细胞中纯化外泌体，然后使用氯化钙（Cacl）改性溶液富集 miR-34a。在富集的 TEXs 中检测到 miR-34a 表达后，检测不同浓度的 TEXs 或 TEX-miR-34a 处理的 CT-26 细胞的活力。此外，还评估了细胞的凋亡率，并测量了同时接受 TEX-miR-34a 和 TEX 的 CT-26 细胞的迁移。然后，在处理后的 CT-26 细胞中测定 miR-34a 靶基因的表达，如 IL-6R、STAT3、PD-L1 和 VEGF-A，这些基因在肿瘤进展中发挥作用。
结果
用 TEX-miR-34a 处理 CT-26 细胞后，观察到细胞活力降低，细胞凋亡水平也呈剂量依赖性增加。TEX-miR-34a 能够降低 TEX-miR-34a 处理细胞的迁移率，并显著限制 IL-6R、STAT3、PD-L1 和 VEGF-A 的表达。此外，TEXs 本身可以增加肿瘤细胞的凋亡率，并抑制这些细胞的增殖和迁移，而 TEXs 与 miR-34a 富集后则会增强这些作用。
结论
从饥饿的 CT-26 细胞中分离出的外泌体具有将 miR-34a 递送到肿瘤细胞中的潜力，并且能够很好地维持 miR-34a 的功能，在调节与肿瘤进展相关的基因方面具有很高的功效，而 TEXs 对肿瘤细胞没有积极作用，可能在 CRC 治疗中作为一种有利的辅助剂。
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